Aluminum cleaning composition



gives unsatisfactory results.

United States Patent f 2,907,649 ALUMINUM CLEANING COMPOSITION :BernardBerkeley, Hempstead, and Arthur Petersen, Brooklyn, N.Y., assignors toCommonwealth Products, Inc, Kalamazoo, Mich., a corporation of MichiganNo Drawing. Application August 5, 1957 Serial No. 676,365

4 Claims. c1, 51-304 is useful for cleaning and polishingalurninumarticles and. which maybe used without danger by unskilled persons withcompletely satisfactory results.

Aluminum and its alloys used in cookware become stainedand discoloredduring normal use in the preparation of foodstuffs. Mechanical removalof stains and discolorations with scouring powders or with soap andsteel wool is laborious and time-consuming and very often Further, suchcleaning procedures completely fail to remove discolorations if thesurface is irregular, roughened or pitted. I, [It is known that aluminumcan be cleaned by surfacerenewing chemical type cleaners. For example,it is known to clean aluminum by applying inorganic or or- -isundesirable for many purposes, such as from a housewifes viewpoint.Further, the use of such cleaners usually is comparatively timeconsuming and in manyinstances necessitates special cleaning techniqueswhich makes such cleaners less than completely satisfactory,particularly, for home use.

Accordingly, it is an object of this invention to provide an improvedacid-abrasive type of aluminum cleaning composition primarily adaptablefor use with aluminum cooking utensils.

It is a further object of this invention to provide an improvedacid-abrasive type of aluminum cleaning composition which willeffectively remove discolorations from aluminum surfaces, particularlyaluminum cooking utensils, and which will impart a high lustre to thecleaned surface and which, after such cleaning is completed, will leavea protective film on such surface.

It is a further object of this invention to provide an improvedacid-abrasive type aluminum cleaning composition which will not beharmful to the users clothing or person and which may be convenientlyused by unskilled persons following conventional, well understoodtechniques for cleaning utensils.

Other objects and advantages of this invention will be apparent to thoseacquainted with aluminum cleaning compositions upon reading thefollowing description.

We have discovered that a composition consisting of acid producingmaterials such as oxalic acid and sodium bifluoride will speedilybrighten discolored aluminum when applied to the aluminum and dissolvedin water. By incorporating in the acid producing materials a fatty acidor material capable of forming a fatty acid in acid 2,907,649 PatentedOct. 6, 1959 solution, and an abrasive, the matte effect created by theacid can be reduced and a high lustre can be imparted to the aluminumsurface. a

The acid producing materials preferably include a strong dibasic organicacid and an acid salt of a metal fluoride. The preferred organic acid isoxalic acid. Maleic acid also appears suitable. The acid salt of a metalfluoride is preferably sodium or potassium bifluoride. Potassium orsodium fluoride may also be used but with less satisfactory results.

In order to produce a lustrous finish on the aluminum surface it isessential to provide a substance capable of supplying fatty acid in acidsolution. The preferred fatty acid supplying substance is a powderedalkali soap particularly a tallow base, sodium soap such as powderedIvory soap, available from Procter & Gamble Co., Cincinnati, Ohio.However, other soap bases having a high proportion, as at least about40% of saturated fatty acids are also suitable. It is preferred that thesoap base include primarily fatty acids ranging from C upwards and thatthe soap be solid at room temperature.

The abrasive used in the composition may be any one of a variety offinely ground abrasives, usually 200 mesh or smaller, such as feldspar,tripoli, diatomaceous earth, silica etc. A preferred abrasive isfeldspar (200 mesh), available from Ball Mining Co.; Bates (West Paris),Maine.

It is desirable, though not essential to incorporate in the cleaningcomposition a small amount, as 1% by weight, of a wetting agent. Acomposition containing suchan agent shows increased wetting and surfaceaction and also improved chemical cleaning properties. A suitablewetting agent is a sodium alkyl aryl sulfonate composition availablefrom National Aniline Division, Allied Chemical & Dye Corporation, NewYork 6, New York.

A range of compositions for accomplishing speed chemical cleaning actionand formation of a high gloss on an aluminum surface is as follows:

Parts by weight The above ingredients are powders at room temperature.The composition is manufactured by mixing the powdered ingredients in apowder mixer or similar apparatus until the mixture is uniform.

The cleaning composition is applied to the aluminum surface to becleaned by sprinking the powder upon the surface. The surface may bewetted with water before and/or after the powder is applied thereto. Theacid producing chemicals of the wetted cleaning composition attack thealuminum surface to effect the desired cleaning thereof. Immediatelyafter application or after a time lapse of a few seconds, if desired,the surface is rubbed in order to enhance the cleaning action and toimpart a lustrous finish to the surface. The cleaning composition isthen rinsed off the surface.

While the phenomena involved in the use of the cleaning composition arenot completely understood, it is believed that the acid producingmaterials when wet with water not only attack and remove the aluminumoxide num soap thereon.

layer stains and discolorations from the aluminum surface but also reactwith the soaps to liberate fatty acids. These fatty acids react with theclean aluminum surface when said surface is rubbed to form a coating ofalumi- The aluminum soap coating tends .to prevent reformation of atarnish layer on the surface. The foregoing suggestions as to thereactions involved in the use of the cleaning composition, whilebelieved to 'be correct, are offered solely for purpose of providing onepossible explanation of the phenomena involved.

It is tobe understood that the invention is not dependent upon thecorrectness of these suggestions and, therefore, the invention should beinterpreted accordingly.

Minor amounts of other ingredients may be incorporated-in the cleaningcomposition for special purposes. For example, afoaming agent may beincorporated in the composition'to provide a sudsy product. Also, aningredien-t may-be added for the purpose of preventing caking, if suchis necessary or desirable.

Although a particular preferred embodiment of the invention has beendisclosed herein for illustrative purposes, it will be understood thatthe invention includes such modifications or variations thereof as liewithin the scope ofthe appended claims.

We claim:

1. A powdered aluminum cleaning composition, consisting essentially ofabout 1-20 parts by weight oxalic acid, about 1-20 parts by weightsodium bifluoride, about 1-20 parts of weight of a soap capable ofliberating fatty acids in acid solution, at least about 40% of the fattyacids being saturated, and about 9639 parts by weight of finely groundabrasive.

2. A method of cleaning an aluminum surface, including the steps:wetting said surface with water; applying to said surface a powderedcleaning composition consisting essentially of between about 1 and about20 parts by weight oxalic acid between about 1 and about 20 parts byWeight sodium bifluoride, between about 1 and about 2 0 parts of weightof asoap capable of liberating fatty acids in acid solution, at leastabout of the fatty acids being saturated, and between about 96 and about39 parts by weight of finely ground abrasive and rubbing said surface toremove tarnish, stains and discolorations from said aluminum surface andto impart a high lustre thereto.

3. An acid-abrasive composition for cleaning aluminum ware comprisingfrom 1-20'parts by weight of a fluoride salt selected from the groupconsisting of sodium bi-fluoride, potassium bifiuoride,'sodiumfiuoride'and potassium fluoride; from 1-20 parts by weight of a strongorganic acid selected from the group consisting of oxalic acid andmaleic acid; from 1-20 parts by weight of a fatty acid supplyingsubstance, said substance being capable of liberating fatty acids inacid solution, at least about 40% of the fatty acids being saturated;and from about 96-39 parts by weight of finely ground abrasive.

4. An acid abrasive composition for cleaning aluminum ware comprisingfrom 1-20 parts by weight of a fluoride salt selected from the groupconsisting of sodium bifluoride, potassium bifluoride, sodium fluorideand potassium fluoride; from 1-20 parts by weight of oxalic acid; from1-20 parts by weight of a soap capable of liberating fatty acids in acidsolution, at least about 40% of the fatty acids being saturated; andfrom about96-39 parts by weight of finely ground abrasive.

References Cited in the file of this patent UNITED STATES PATENTS190,407 Bertram May 8, 1877 978,747 Higgins Dec. 13, 1910 1,240,544Damon Sept. "18, 1917 1,890,214 Churchill Dec. 6, 1932 2,112,632Montgomery Mar. 29, 1938 2,571,690 Dobbelmann et a1. Oct. 16, 19512,628,199 Lowenheim Feb. 10, 1953

1. A POWDERED ALUMINUM CLEANING COMPOSITION, CONSISTING ESSENTIALLY OFABOUT 1-20 PARTS BY WEIGHT OXALIC ACID, ABOUT 1-20 PARTS BY WEIGHTSODIUM BIFLUORIDE, ABOUT 1-20 PARTS OF WEIGHT OF A SOAP CAPABLE OFLIBERATING FATTY ACIDS IN ACID SOLUTION, AT LEAST ABOUT 40% OF THE FATTYACIDS BEING SATURATED, AND ABOUT 96-39 PARTS BY WEIGHT OF FINELY GROUNDABRASIVE.